676  Mr.  G.  B.  Dyke  on  the  Use  of  the  Cymometer 
frequencies  n±  and  n2  induced  in  the   secondary  circuit  and 
the  natural  frequency  ??0  : — 
Vl  +  k> 
n2 
or 
k> 
k 
n2       ^T+  k  ' 
Now  in  the  case  of  some  oscillation  transformers  used  in 
wireless  telegraphy  the  coupling  may  be  about  0*5. 
Hence  we  should  then  have 
7u      V  1-5      1-732 ' 
or,  The  frequency  of  one  wave  is  about  If  times  that  of  the  other. 
For  a  coupling  of  the  order  of  0'5  the  method  above  de- 
scribed may  be  applied  to  each  hump  of  the  double-humped 
resonance-curve,  and  will  enable  a  fairly  accurate  determi- 
nation of  the  decrements  of  the  two  oscillations  to  be  made; 
but,  as  shown  by  C.  Fisher  (see  Annalen  der  Physih,  vol.  xix. 
p.  182,  1906),  when  the  coupling  is  very  loose  we  cannot 
consider  the  resultant  resonance-curve  to  be  identical  with 
the  sum  of  the  curves  due  to  each  oscillation  separately. 
14 
f\ 
*■> 
/•"  V 
1 
//     ' 
\  \_ 
y / 
I 
%s*~ 
-"" 
\    \ 
/! 
=T^^ 
r 
F 
-equ.ency 
.7X,. 
1-0 
1-3 
1-4      T5X106 
The  curve  shown  in  fig.  3  was  taken  from  a  closely  coupled 
circuit  of  this  type,  and  may  be  taken  as  indicative  of  the 
general  type  of  result  to  be  expected. 
